1. Field of the Invention
The present invention relates to a refrigerating system having, on an air inlet side of a condenser for condensing a refrigerant, a receiver of elongated tubular shape of a length corresponding to the dimension of the condenser, and the refrigerating system can be suitably used for an air conditioning system for a vehicle.
2. Description of Related Art
A refrigerating system for an air conditioning system for a vehicle includes, generally, a compressor, a condenser, a receiver, a pressure reducing device, and an evaporator, which are arranged in a refrigerant recirculating line. The condenser and the receiver must be arranged in separate locations in an engine compartment of the vehicle, which only has very limited available space. As a result, it has heretofore been required that an improved construction of the air conditioning system, capable of being fitted in a reduced space in the engine compartment was provided.
In order to reduce the space that the air conditioning system occupies in an engine compartment, a Japanese Un-Examined Patent Publication 60-138379 proposes a refrigerating system for a vehicle, where a refrigerant receiver formed as an elongated pipe of a length corresponding to a dimension of a refrigerant condenser is arranged in front of an air inlet of the condenser, so that the elongated receiver is inclined at a predetermined angle .theta. with respect to a horizontal direction. In this prior art construction, a value of the inclined angle as small as, for example, about 20.degree. with respect to a horizontal direction can reduce a vertical component in the velocity of a refrigerant flowing in the receiver. As a result, even when a large amount of the recirculated refrigerant, due to a high rotational speed of the compressor, is circulated the gas to liquid boundary in the receiver is not disturbed. This allows only a liquid-state refrigerant to be supplied to the condenser.
In the prior art construction, when a dimensional limitation exists in enlarging the width of the refrigerant condenser, there may arise a situation that the inclination angle .theta. of the receiver is increased to 40.degree. or more, which causes the vertical velocity component to become large in the flow of the refrigerant in the receiver, which causes the refrigerant to bubble in the receiver, which prevents a gas-liquid boundary from being properly maintained. As a result of such a lack of a gas-liquid boundary, the refrigerant from the receiver is issued to a pressure reducing device in the refrigerating cycle as a mixed gas and liquid. As a result, a reduction in the amount of the liquid state refrigerant in the pressure reducing device occurs. Furthermore, an in-flow of the gaseous refrigerant to the pressure reducing device occurs, which causes the pressure reducing device to be subjected to hunting, which causes the refrigerating performance to be reduced.
Furthermore, in case of a vehicle having an air conditioning system having a supercooler between the receiver and the pressure reducer, an imperfect separation of the gaseous medium from the liquid state medium makes it impossible to obtain a desired supercooling performance, which also causes the cooling efficiency to be reduced.